Airplane flotation system



Sept. 30. 1930.

3 Sheets-Sheet Filed Oct. 18, 1929 7 3 6 I. Z Z 9 I 4 Z 0 Z 7 Z 0 3 4 2 Z 4 2 7 4 345 444 g 6] 4 34 0 Cr 2 wow 0 6' o c 9 k 3 62 5 3 4 4 O 7 M 39 6 Q 4 .2 Z Z 5 O Z 6 Z w INVENTOR Sept. 30, 1930. F.""M. SALISBURY 1,776,855

A IRPLANE FLOTATION SYSTEM Filed 001;. 18, 1929 3 Sheets-Sheet .2

69 INVENTOR P 30, 1930. F. M. SALISBURY AIRPLANE FLOTATION SYSTEM Filed Oct. 18, 1929 5 Sheets-Sheet Patented Sept 30, 193G UNITED m nu-m OFFICE ERANK SALISBURY, F DUNDALK, MARYLAND, ASSIGNOR TO THE GLENN L; EABTIN so, or nan'rnconn, MARYLAND,

A CORPORATION OF MARYLAZND AIRPLANE nornrron' SYSTEM Application filed October 19, 1929. SeriaLNo. 400,568.

My invention relates to aircraft emergency I ity, simplicity and efliciency. It is the result of continuation in the development of the emergency flotation system comprisin the subject matter of a joint application erial The instant application is based on the fact that, in the event of a forced landing upon water, an airplane will sink unless eifective provision ismade to float it and on the experience gained by practical operation of airplane emergency flotation systems in service which' indicated that further development was necessary if their maximum effectiveness was to be attained.

The inventions which comprise the two identified applications involve to some extent the use of similar apparatus but theinstant invention substitutes a rearwardly located, inverted open bag adapted to act as a flotation body fdr the tail section in lieu of the closed rear bag heretofore used and functions in a manner diflering from that described in the earlier application insofar as control of the sealing function of cylinder-piston control mechanisms and the method of inflation of the rearwardly located flotation bag are concerned and in addition a balanced flotation is obtained.

One object of my improved system is to assure the floating of a disabled aircraft when it is compel ed to ali ht upon water.

Another object is to simplify the operation of an emergency flotation system.v

Another object is to reduce the weight, number and cost of parts comprising an emergency flotation system.

Another object is to economize space by more efficiently utilizing that which was formerly occupied by a deflated compacted rear bag, its storage compartment, transfer valve mechanisms and higher capacity pressure reservoir. l

Another object is to 1solate-flotation bags from each other after their initial inflation thus to prevent excessive accidental loss of flotation gas.

Another object is to enable the pilotto controlthe reverse flow of flotation gas from the bags.

Another object is to enable the pilot to control the relative buoyancy of the bags in the'system to vthus balance his craftupon the water.

- Apparatus of this character is required to be simple, light, occupy a minimum of space when not in use, not introduce parasiticresistance, when emergency arises it is imperative that it shall function instantly-With a minimum expenditure of time-and eifort on'the part of the pilot, Inflatable bags fore and aft have been used as a means of floating a' disabled airplane but experience with the auxiliary apparatus required for their oper-. ation has shown that deficiencies existed in the systems. Compressed air'to be used for inflating the bags required cumbersome tanks of considerable weight for retention of an adequate supply of air to provide sufficient displacement to support the weight of an airplane and the crew. Substitution of a bottle of liquefied CO gas solved the problem of excessive weight and space occupied-by the type of pressure tank formerly used but it introduced other difficulties which are over: come by the instant invention. For example, the rapid ex ansion of liquefied CO gas when release from the bottle, to the pipes leading to the flotation bags caused rapid fall in temperature, a temperature so low as to destroy'the eflectiveness of check valves as heretofore used in systems of this type, in fact the valve elements were frozen together. Freezing of the valves-frequently caused the isolation of one or more bags from the system thus concentrating the gas pressure to the remaining bag and causing its disruption. The exceedingly small increment of time required for the bags to inflate from a source of pressure amounting to approximately 1000 pounds per square inch neccessitates the releaseof the bags from their storage compartments in advance of inflation that serious damage to the aircraft structure be prevented. 2

The system herein described and illustrated comprises forwardly located inflatable bags withtheir storage compartments and associated mechanisms in number and size as required by the weight and design of the airplane together with a rearwardly located open flotation bag which automatically entraps air when more or less submerged in water. This type of bag does not require a storage compartment or door release mechanism because it is not ejected from the fuselage. The elimination of a rear compacted flotation bag together with the associated storage compartment, door release and transfer valve mechanism, and the substitution of an inverted open bag conserves the space formerly occupied by a bag compartment thereby making itavailable for cargo storage. In addition to the reduction of weight by the aforesaid eliminations, a reduction in capacity and weight of tanks re uired for storage of liquefied gas required or initial inflation of the forwardly located bags is ob-' tained. The forwardly located bags are normally deflated and stored in compartments within the fuselage adjacent the outer surface of the craft which location is such as not to offer resistance to the airstream.

The compartments are normallyclosed by locked doors, preferably spring hinged, to automatically open outwardly when'released by their locks. Means is provided wherelzly the locks are automatically opened in a vance of bag inflation that the bags may not meet with resistance when leaving their compartments. Novel locking and pressure transfer mechanism is provided by which unlocking and opening of doors followed by inflation and ejection of the forwardly located bags is assured in proper sequence for reliable and safe operation. Gas for inflation of the forward gas bags is obtained from a liquefied CO supply because of the minimum volume and weight occupied by a high pressure storage reservoir of this type which may be stored in any available place, to more efficiently utilize a limited space.

The solution of the enumerated problems -was still short of applicants objective, viz,

the provision of a com lete flotation system which will function effectively under ultra adverse conditions such for example as the loss of stored gas pressure previous to requirement for emergency flotation; 'or, loss of flotation due to rupture of a bag or of the pipe leading thereto; or, in case of a ruptured bag, loss of gas from the intact bags through the pipe-lines leading to the defective bag; or to un alancing of the craft due to shifting the center of gravity. The instant invention guards against these specified contingencies by providing manually o erated means whereby compressed air supp em'ents or replaces that from the CO pressure storage tank, to reinflate the remaining bags thereby enabling the ilot to float his craft and to apportion disp acement fore and aft thereby preventing disaster due to changed position of the centers of buoyancy and caused by the crew being compelled to leave the cockpit and find refuge on the wings or top. of the fuselage. If the center of buoyancy locates directly above the center of gravity the-craft will balance, otherwise the tail section will rise or fall until the aforesaid condition is corrected by the pilot. The instant invention provides means by which the pilot can balance his craft when it is floating upon the surface of water.

My system will be understood by reference to the following identified drawings, their description and the explanation of the mode of operation.

Fig. 1 is a plan view of the forward portion of an airplane cut away to show the interior arrangements of certain elements of my flotation system but omitting all flight control mechanisms which are not involved in my invention. v

Fig. 2 is a plan view ofone of my cylinderpiston mechanisms as adapted to act as a pressure transfer valve, manually operable pressure seal and to operate a door latch mechanism. j

Fi .3 is a view of the mechanism of Fig. 2 100 ing at thelpiston rod end.

F i 4 is a view of the mechanism of Fig. 2100 ing at the end opposite to that ofFig.

Fig. 5 isa cross-section ofmechanism F ig. 2 with addition of a push rod extension to the piston rod thereby adapting it to act as a latch for the storage compartment door and as means for manually reversing the position of the piston head as a valve member.

Fig. 6 is a plan view of an airplane cut away to show the interior arrangements of the elements as shown in somewhat different arrangement but operating the same as in Fig. 1 andto show the addition of an inverted open flotation bag in the tail section.

Fig. 7 is a cross section thro'u h C C of Fig. 6 to show my inverted open otation bag supported by fastening to the bulkheads within the fuselage and adapted to float the tail section when it becomes more or less submerged in water.

Fig. 8 is a cross section A-A of an air pressure control valve as shown in Fig. 6.

Fig. 9 is across section BB of the valve showing the operating handle and valve disc turned to a different position from that shown in Fig. 8.

Fig. 10 is a side elevation view of an airplane partially submerged in water and require a floated by forwardly and rearwardly located flotation bags.

Fig. 11 is a front elevation view of the floating airplane illustrated in Fig. 10 and showing an ejected bag at each side of the fuselage.

In .Fig. 1 an airplane fuselage is shown in outline at 15, wings16, power plant and propeller 17, flotation bag storage, compartments 18, storage compartment doors 19, spring hinges 20, door catches 21, piston rods 22, piston rod lock members 23, cylinderpiston valve mechanisms 24-25, attached by lugs 26 to fuselage 15', piston heads 27, flotation bags 28-29 attached by cables 30 to fuselage 15, high pressure gas reservoir 31, gas valve 32, gas valve opening cable 33, cable handle 34, outlet pipe leads from valve 32 to ,branch pipes 36 which lead to inlets 37 of cylinder-piston mechanisms 2425, flexible tubes 3839 lead from out lets 40 of cylinder-piston mechanisms 24-25 to flotation bags 2829. Cable 41 is attached at one end to piston rod 22 at 42 and at the' other end to ring 43.' A support 44 is provided for ring 43 when in position to release piston rod 22. A spring 45 is attached at 46 to fuselage 15 and is provided with a hook 47 for a purpose hereinafter described. Pipes 48 -49 lead from cylinder-piston mechanisms 2425 to valve 50 which is provided-with an operating handle 51. Pipe 52 leads from valve 50 to a conventional air pump 53 which is provided with operating means 54.

In Fig. 5 is shown interior details of cylindcr-piston mechanisms 24-7 25 and their associated iston rod and lock members. Piston head 2 and lock members 23 are shown by solid lines in its initial position previous to inflation of flotation bags and also subsequent to their inflation. The pistons, 24-25 and lock members 23 are shown by dotted lines in position immediately following the release of gas from reservoirs 31 to inlets 37. At 55 is shown a packing washer adapted to seal the opening through the cylinder head around piston rod 22 at 56-when piston head 27 is forced to the dotted position by high pressure entering the cylinder at 37 and acting on piston head 27.

in Figs. 6 and 7 is shown the system of Fig 1 with my improved devices incorporated therein. Corresponding parts of Fig. 1 are correspondingly numbered. At 60 is shown a flotation bag differing from bags 28 -29 in respectto the method of inflation, it does not storage compartment, release mecimnism or initial inflation by means other than the entrapping of air when its lower portion is submerged in Water. It is fastened in position as by cables 61 attached to fuselage 15 at 62. Portions of elevator and rudder controls are shown at 63.

Cross sectional View Fig 7 is talgen through CC of Fig. 1 to show the open bottom por: tion of rear flotation bag 60 and to show the manner of its normal suspension fromthe fuselage members, whereas under water flotation conditions it is forced upward against the fuselage members by entrapped air pressure. At 64 is shown a pipe leading from bag 60 to a valve 65 which is shown in cross section by Fi s. 8 and 9. I

Manual in ation and buoyancy control Valve 65 is illustrated by Figs. 8 and 9 and comprises a body 66' supported by a structural member 67in any convenient manner. Body 66 has a chamber 68 communicating with inlet 69 and outlets 7071-7273. A disc valve member 74 is retained against a ground seat on the interior wall of body 66 by spring 75 and is adapted to be rotated by handle 76. Valve disc 74 is, provided with two radially disposed slots in its contacting surface one of which 77 communicates with chamber 68 and the other 78 is adapted to communicate outlet 73 with eitheroutlet 70-717 2 according to the instant position of disc 74 as controlledby handle 76 or to a ppsition wherein chamber 68 is closed.

anual pressure applied to handle 76 against spring75 unseats disc valve member 74 thereby opening outlets 707172-73 to chamber 68 and releasing ressure from the rear flotation bag 60 and rom the lines leading to mechanisms 24-25 to atmosphere. A return check valve 79 may be incorporated with chamber 68 and may be seated by spring 75 until unseated by air pressure from pump 253 as shown in Fig. 8, or a check valve may be incorporated with the conventional air pump 53 in lieupf 79. Check valves in the air lines are permissible because the pressure is low compared to that from the CO reservoir and freezing due to' rapid expansion cannot take place. The cubic content design of the two forward bags is equal to the supply of gas within the reservoir and inasmuch as. the rear bag is not inflated bythe CO supply, the size and weight of the reservo reduced from that which would be required for gas supply to a third bag. Elimination of this weight and that of associated mechanism by the instant invention is a very considerable item.

Occasion having arisen for the airplane to alight upon water, the pilot releases gas from the high pressure reservoir 31 through valve 32 by pulling cable 33 with handle 34. High pressure gas then passes through pipes 36 to the inlets 37 of c linder-piston mechanisms 2425, acts on piston heads 27 to move piston rods 22 to a position in which door catches 21'are released from piston rod lock members 23 to thus permit spring hinges 20 to open doors 19, and in which position piston head 27 opens outlets 40 to inlets'37 thus releasing the high pressure gas through tubes 38-39 to forward flotation bags 28*29. The storage compartment doors 19 havin opened provides free exit of two forward bags to the position shown in Figs. 6, 10, 1].. A rear bag is not shown in Fig. 1, because non-adjustable flotation means are assumed to more or less float the tail section.

After release of gas from the high pressure source to the cylinder-piston door release and transfer valve mechanisms and its passage thereafter" to the forward flotation bags, the pilot pulls cable 33 to move piston head 27 to an intermediate position within its cylinder thus isolating the inlet port 37 from the outlet port 40 to prevent flow of gas to or from either bag through pipe 38 and places cable ring 43'on the hook 47 attached to spring'45 which is fastened to the fuselage structure zit-'46. Thereafter at the time of servicing the flotation system, replacement of high pressure reservoir 31 and replacement of the forward bags in their storage compartments, the pilot returns cable ring 43 to position 44 at which it remains until the system is again brought into use. 'Inthe event that removal of the cable ringfrom hook 47 is overlooked and to guard against subsequent failure of the system due to that fact spring 45 is provided and which is normally in a free condition whether or not the cable ring is placed on the associated hook. In the event of again operating the flotation system, piston rod 22 ulls cable41 and extends spring 45 accordingly. In the absence of this precaution and should the pilot fail to remove ring 43 from support 44, piston head 27 would be restrained by cable 41 to a position wherein entrance of pressure to bag 28 from. cylinder 24 is impossible and high pressure gas from reservoir 31 would then. concentrate incylinder 24-25 and bag 29. Inasmuch as the combined design capacityyof the two bags is such as to balance the Volt} ume of gas contained in reservoir 31 after expansion, failure to inflate one bag over loads the other by 100% thereby quite likely causing disru tion of the remaining bag, loss of the aircra t and jeopardizing the lives of the members of the crew. p The emergency landing upon water hav-"' ing been accomplished it then becomes necessary to balance the craft, in other Words to restore the center of buoyancy. In the event that the tail of the craft is riding higher than the forward end, the transfer valve (35 can be turned to a position shown in Fig. 9 wherein the air entrapped in the rear bag as shown in Fi 10 is permitted to escape through vent and the tail of the craft will assume a level position in relation to the forward end. Conversely, if the tail of the craft is lower than the forward end, valve can he turned to a position shown in Fig; 8 at 77 wherein air can be forced into the rearwardly located bag by the manuallyoperable air pump 53 to thus bring the tail on a level with the forward end.

In the event that the right wing of the craft tilts downward due to insufficient inflation of the corresponding bag, the transfer valve 65 can be turned to a position as shown in Fig. 8 at 77 wherein the manually operable air pump 53 can increase the displacement of the bag to thus restore the craft to balance.

In the event that the left wing of the craft tilts downward, the valve 65 can be turned to a position opposite to that shown in Fig. 8 at 77' wherein air can be forced into the flotation bag by the manually operable air pump 53 thus restoring the craft to balance.

In the event that a lateral unbalanced condition is caused by shifting of the position of the crew, the valve 65 can be turned to a position corresponding to the valve outlet leading to the highest bag and wherein flotationgas can escape from the bag to thus restore equilibrium of the craft.

Having described my invention I claim,-

1. In an aircraft emergency flotattion system inflatable-closed bags attached to said aircra ,meansforinflatingsaidbags,aninverted open bag located within said aircraft,said open bag adapted to entrap air when its opening is submerged in water, the relative size and location of said bags on said aircraft adapted to substantially uniform flotation of said craft upon water.

2. In an aircraft emergency flotation system closed inflatable bags attached to said aircraft, means for inflating said bags; an inverted open bag located within said aircraft, said open bag adapted to entrap air-when its opening 'is submerged in water, means for varying the displacement volume of said open 1 bag whereby substantially uniform longitudinal flotation of said aircraft is obtained.

3. In an airplane, an emergency flotation system comprising a multiple number of inflatable closed bags attached to and laterally located forwardly in relation to the fuselage structure of said airplane, manually controlled means for inflating said bags; an inverted open bag rearwardly located within said fuselage, manuallyo erable means for inflating said open bag; said open bag ada ted by its entrap ed air capacity and coaction with said closedbags to float the tail section of said airplane.

4. In an airplane, an emergencyflotation s stem comprising a multiple number of inatable closed bags attached to and laterally located to float the forward section of the fuselage structure of said. airplane, manually controlled means for inflating said bags; an inverted open hag rearwardl located within said fuselage and adapted by its entrapped air capacity to float the tail section of said airplane.

5. In an airplane, an emergency flotation menting the inflation of either of said bags,-

said bags; an inverted open bag attached to and rearwardly located within said fuselage, 1

means for regulating the inflation displacement of said inverted bag, supplemental man'- ually operable means for selectively supplewhereby flotation is obtained proportionate to the unbalanced weight of said airplane.

6. In an airplane, an emergency flotation system comprising a multiple number of inflatable bags attached to and laterally located forwardly in relation to the fuselage structure of said airplane, manually controlled means for inflating said bags; aninverted open bag rearwardly located within said fuselage'and adapted by its air trapping capacity to float the tail section of said airplane means for manually eontrolling the displacement volume of said inverted open bag.

7. In an airplane, an emergency flotation. system comprising a multiplenumber-of inflatable bags attached to and laterally located forwardly in relation to the fuselage structure of said airplane, manually controllable means for inflating said bags; an inverted open bag rearwardly located within said fuselage and adapted by its air trapping capacity to float the tail section of said airplane means for simultaneously reducing the displacement volume of said bags.

8. In an airplane, an emergency flotation system comprising a multiple number of inflatable closed bags attached to and laterally disposed forwardly in relation to the fuselage structure-of said airplane, means for ejecting said bags from said fuselage, means for in-.

flating said bags; an inverted open bag at tached to and rearwardly located within said fuselage, manually operable supplemental means for selectively inflatinv either of said bags and for regulating theqhflation displacement of said inverted bag. 1 '9. A flotation bag and a cylinder-piston transfer valve control mechanism in. combination comprisingan inflatab bag, a hollow cylinder having an inlet po an outlet port in said cylinder communicating with said bag, a closure cap on theinlet end and ahead having a hole therethrough on the outlet end of said cylinder, a piston head adapted to longitudinal movement within said cylinder, a

piston rod attached at one end to said piston head and longitudinally guided through said hole in said head, a remote controlgmanually operable cable attached to said rod, whereby ressure enters the inlet of said cylinder said pressure forces said piston head past said outlet to thus transfer said pressure to said bag from said cylinder and whereby and thereafter tension manually applied to said cable moves said piston head to an intermediate position between said inlet and outlet ports to isolate said ports from each other to'thus prevent return flow of said fluid from said bag through said cylinder;

10. A cylinder-piston transfer valve mechanism comprising in combination a hollow cylinder having an inlet port and an outlet port longitudinally located through its wall, a closure cap on the inlet end and'a head having a hole therethrough on the outlet end of said cylinder, a. piston head adapted to longitudinal movement within said cylinder, a piston rod attached atone end to said piston head and longitudinally guided through said hole in said head, a remote control manually operable cable attached to said rod, resilient means associated with said cable and said rod to restrain said piston head to an intermediate position between said inlet and said outlet ports, whereby when fluid pressure enters the inlet of said cylinder said pressure forces said piston head past said outlet to thus transfer said pressure to said outlet of said cylinder and whereby upon substantial reduction of said pressure said cable returns said piston head to said intermediate position thereb isolating saidports from each other. 11. n an airplane flotation system, a flotat1o1i bag, a cylinder-piston transfer valve mechanism comprising in combination a hollow cylinder having an inlet port and an outlet port longitudinally located through its wall, said outlet port communicating with said bag, a closure cap on the inlet end and a head having a hole therethrough on the outlet end of said cylinder, a piston head adapted to longitudinal movement within said cylinder, a piston rod attached at one end to said piston head and longitudinally guided through said hole in said head, a packing washer mounted upon said (piston rod within said cylinder bepiston head past said outlet port to inflate said baggd compresses said washer between said hea s thereby sealing the cylinder chambea against leakage from saidbag past said IO 12. In an airplane emergency flotation system, a selective control valve mechanism asso ciated therewith comprising a body member having a chamber; an inlet 'thru a wall of. said chamber, a multiple number of outlets and a vent thru a SBCOIldgWflll'Of said chamher; a check valve member adapted to close said inlet against reverse flow of fluid therethru; a rotatable disc Valve member multiply slotted on one face and located within said chamber, one of said slots extending to the periphery of said disc, a rotatable shaft attached to said disc and extending through said second wall of said chamber, a handle attached to said shaft; a compression spring adapted to simultaneously restrain the slotted face of said disc L0 intimate contact with said wall of said chamber and to seat said check valve member; said disc adapted by its relation to said outlets and by rotation of said shaft to selectively register either of said out lets with said slot leading to said chamber, or to close said outlets from each other and said chamber, or to register one of said slots with one of said outlets and said vent, and whereby depression of said disc by manual pressure on said handle releases said disc from the wall of said chamber to simultaneously vent said chamber and said outlets to atmosphere through said vent thereby con trolling the flotation characteristics of said system.

13. In an airplane emergency flotation system, a selective control valve mechanism associated therewith comprising a body member having a chamber; an inlet thru a wall of said chamber, a multiple number of outlets and a vent thru a second wall of'said chamber; a rotatable disc valve member multi ply slotted on one face and located Within said chamber, one of said slots extending to the periphery of said disc, a rotatable shaft attached to said disc and extending through said second wall of said chamber, a handle attached to said shaft; a compression spring adapted to restrain the slotted face of said disc to intimate contact with said Wall of said chamber, said disc adapted by its relation to said outlets and by rotation of said shaft to selectively register either of said outlets with said slot leading to said chamber, or to close said outlets from each other and said chamber, or to register one of said slots with one of said outlets and said vent, and whereby depression oi saiddisc by manual pressure on said handle releases said disc from the wall of said chamber to simultaneously vent said chamber and said outlets to atmosphere through said vent, thereby controlling the fiotation characteristics of said system. i

14. In an airplane emergency flotation system, means for inflating the flotation bodies of said system, means for supplementing the inflation of said bodies, a selective control valve mechanism associated with said supplemental means and said bodies comprising a member having a chamber; an inlet thru a Wall of said chamber, a multiple num ber of outlets and a vent thru a second wall of said chamber; a rotatable disc valve member multiply slotted on one face and lo cated Within said chamber, one of said slots extending to the periphery of said disc, a 1'0- tatable shaft attached to said disc and extending through said second Wall of said chamber, a handle attached to said shaft, a compression spring adapted to restrain the slotted face of said disc to intimate contact with. said wall of said chamber, said disc adapted by its relation to said outlets and 1,77aee5 by rotation of said shaft to selectively register either of said outlets with said slot leadsaid outlets to atmosphere through said vent.

In testimony whereof, I hereunto afiix my signature. 1

FRANK M. SALISBURY. 

